name : v8-weak-callback-info.h // Copyright 2021 the V8 project authors. All rights reserved. // Use of this source code is governed by a BSD-style license that can be // found in the LICENSE file. #ifndef INCLUDE_V8_WEAK_CALLBACK_INFO_H_ #define INCLUDE_V8_WEAK_CALLBACK_INFO_H_ #include "v8config.h" // NOLINT(build/include_directory) namespace v8 { class Isolate; namespace api_internal { V8_EXPORT void InternalFieldOutOfBounds(int index); } // namespace api_internal static const int kInternalFieldsInWeakCallback = 2; static const int kEmbedderFieldsInWeakCallback = 2; template <typename T> class WeakCallbackInfo { public: using Callback = void (*)(const WeakCallbackInfo<T>& data); WeakCallbackInfo(Isolate* isolate, T* parameter, void* embedder_fields[kEmbedderFieldsInWeakCallback], Callback* callback) : isolate_(isolate), parameter_(parameter), callback_(callback) { for (int i = 0; i < kEmbedderFieldsInWeakCallback; ++i) { embedder_fields_[i] = embedder_fields[i]; } } V8_INLINE Isolate* GetIsolate() const { return isolate_; } V8_INLINE T* GetParameter() const { return parameter_; } V8_INLINE void* GetInternalField(int index) const; // When first called, the embedder MUST Reset() the Global which triggered the // callback. The Global itself is unusable for anything else. No v8 other api // calls may be called in the first callback. Should additional work be // required, the embedder must set a second pass callback, which will be // called after all the initial callbacks are processed. // Calling SetSecondPassCallback on the second pass will immediately crash. void SetSecondPassCallback(Callback callback) const { *callback_ = callback; } private: Isolate* isolate_; T* parameter_; Callback* callback_; void* embedder_fields_[kEmbedderFieldsInWeakCallback]; }; /** * Weakness type for weak handles. */ enum class WeakCallbackType { /** * Passes a user-defined void* parameter back to the callback. */ kParameter, /** * Passes the first two internal fields of the object back to the callback. */ kInternalFields, }; template <class T> void* WeakCallbackInfo<T>::GetInternalField(int index) const { #ifdef V8_ENABLE_CHECKS if (index < 0 || index >= kEmbedderFieldsInWeakCallback) { api_internal::InternalFieldOutOfBounds(index); } #endif return embedder_fields_[index]; } } // namespace v8 #endif // INCLUDE_V8_WEAK_CALLBACK_INFO_H_